Search PubMed⌕ Search

Biomedical subjects

H Breuer

Publications and source records attributed to H Breuer.

At least 109 records · Page 6Linked to original sources
PubMed1981

Immunohistochemical demonstration of carcinoembryonic antigen in normal, transitional and inflamed colonic mucosa.

Carcinoembryonic antigen (CEA) had been demonstrated immunocytochemically in normal colorectal mucosa (resection margins of colonic carcinomas), in transitional mucosa (mucosa adjacent to carcinomas), in non-specific proctitis and colitis, and in ulcerative colitis. In the resection margins and in non-specific proctitis and colitis, specific CEA staining is generally observed at the surface epithelium. In transitional mucosa, CEA staining is most intense in branching crypts and at the base of the crypts. In ulcerative colitis, areas with regenerative activity as well as precancerous or cancerous specimens exhibit an intense CEA positive membrane straining. In conclusion, colonic tissue with a high proliferative activity, such as transitional mucosa and ulcerative colitis, show a more intense CEA staining than normal colonic tissue. Moreover, the staining pattern is different in proliferating tissues as compared to normal tissue. A pronounced membrane staining in ulcerative colitis indicates rather a higher proliferative activity than cancer or precancer.

Carcinoembryonic Antigen↗
PubMed1981

[Effect of anaesthesia on the metabolism of noradrenaline in rat brain (author's transl)].

A specific and sensitive method is described for the separation and determination of metabolites of radioactively labelled noradrenaline in very small amounts of brain tissue. This method gives reproducible results, it allows the direct determination of all major metabolites of noradrenaline from the same extract, and is suitable for quantitating a large number of samples in relatively short time. This method was used to investigate how the half-life (turnover) and the metabolism of noradrenaline in rat brain may be influenced by anaesthesia with nembutal. It was found that both the half-life time as well as the metabolism of noradrenaline are reduced during nembutal anaesthesia; in addition, the release of metabolites of noradrenaline into the blood is delayed. When studying the metabolism of neurotransmitters, it has to be considered that nembutal-narcosis influences the metabolic pattern of noradrenaline as well as its temporal changes.

Animals↗
PubMed1980

Measurement by isotope dilution mass spectrometry of 17 alpha-ethynyloestradiol-17 beta and norethisterone in serum of women taking oral contraceptives.

The highly specific and accurate technique of isotope dilution mass spectrometry has been used for the measurement of 17 alpha-ethynyloestradiol-17 beta and norethisterone in serum. Serum samples were obtained from female volunteers who received 2.5 mg lynestrenol and 50 micrograms 17 alpha-ethynyloestradiol-17 beta in two different galenical preparations. The determination of total 17 alpha-ethynyloestradiol-17 beta (conjugated and non-conjugated) was carried out by the following procedure: (1) adsorption of the steroids from 1 ml serum to Amberlite XAD-2; (2) enzyme hydrolysis of the conjugated steroid; (3) addition of 1 ng [6,7-3H2] 17 alpha-ethynyloestradiol-17 beta as internal standard; (4) column chromatography on Sephadex LH 20; (5) derivative formation with heptafluorobutyric anhydride; (6) isotope dilution mass spectrometry at m/z 474 and 478 using a glass capillary gas-liquid chromatography column. For the measurement of norethisterone, which is the major metabolite of lynestrenol, 1 ng [7-3H]norethisterone was added to 0.5 ml serum. The labelled and the non-labelled steroids were extracted and purified by column chromatography on Sephadex LH 20. The norethisterone was reacted to form the 3-enol-17 beta-trimethylsilyl ether of norethisterone and [3H]norethisterone. For isotope dilution mass spectrometry the derivative was injected into the glass capillary column which was coupled to the mass spectrometer. The instrument was adjusted to m/z 442 and 444, corresponding to the molecular ions of the ether derivatives of norethisterone and [7-3H]norethisterone. Accuracy was achieved by the use of highly specific technique of mass spectrometry and the exact control of recovery using the isotope dilution principle. The precision was 4.5% (CV) for the determination of 17 alpha-ethynyloestradiol-17 beta and 2.5% (CV) for norethisterone. The lower limit of detection was at 20 pg ml-1 for both methods.

Contraceptives, Oral↗
PubMed1980

Effect of ethinyl estradiol on renin activity and on the concentrations of renin substrate and aldosterone in plasma of ovariectomized women.

The effect of high doses of ethinyl estradiol (0.4 mg/day) on renin substrate concentration, renin activity and aldosterone concentration in plasma was studied in eight ovariectomized women. Plasma renin substrate (angiotensinogen) increased already within 24--48 h, reaching a maximum on the third to fifth day after starting estrogen treatment. Thereafter, renin substrate concentration remained relatively constant in a range which was fourfold above the baseline levels. The increase of plasma renin activity was less pronounced and showed considerable between-patient variability; this increase was statistically significant only after 48 hours of estrogen intake. A rise in plasma aldosterone concentration was observed in two of four subjects examined. In one patient treated with 5 mg estradiol benzoate intramuscularly, plasma renin activity increased without any measurable change in renin substrate concentration. Only in one subject treated with ethinyl estradiol did plasma renin activity increase before plasma renin substrate concentration; the results presented do not preclude factors other than the stimulation of renin substrate synthesis in the liver from contributing to the activation of the renin-aldosterone axis during treatment with ethinyl estradiol.

Aldosterone↗
PubMed1980

[Second International Expert Meeting of the German Foundation for Cancer Research, "Current trends in cancer research." Critical review of tumour markers in diagnosis and surveillance].

The 2. International Expert Meeting of the "Deutsche Stiftung für Krebsforschung" on "Current Trends in Cancer Research", was held from May 11.-14., 1979, in Bonn. The conference dealt with a special subject: it was dedicated to the critical evaluation of tumor-marker substances with all their possible applications in clinical oncology. The aim was to reach clear conclusions about the real usefulness of tumor-markers in diagnosis and prognosis of cancer, as well as in the surveillance of already diagnosed patients. Moreover, the choice of the most appropriate tumor marker(s) for the different tumors out of the variety of the currently known substances, was to be cleared up. The sequel of the experts' critical considerations resulted in answer to three principle questions; these answers could serve as a basis for recommendations to all clinicians interested in oncology, who already are dealing with tumor-markers or intend to do so.

Carcinoembryonic Antigen↗
PubMed1980

[Diagnostic significance of tumour markers in clinical chemistry. Report on the workshop conference of the German society for Clinical Chemistry, held on November 15--17, 1979 in Schloss Auel (author's transl)].

A workshop conference was held on the diagnostic significance of tumour markers in clinical chemistry. The aims of the conference were (1) discussion of the methodological prerequisites for the standardization of tumour marker determinations, and (2) description of those clinical conditions under which the determination of tumour markers should be carried out. The following aspects were discussed in detail: Sampling, comparison of different methods, standardization and quality control, and pathobiochemical aspects. As far as clinical aspects were concerned, emphasis was laid upon the following points: Screening and limits of early diagnosis, evaluation of tumour growth, prognosis, follow-up studies. In addition to oncofetal tumour proteins, hormones, enzymes, and placental proteins were also discussed.

Antigens, Neoplasm↗
PubMed1980

UDP-glucuronyltransferase. Report on the workshop conference of the German Society for Clinical Chemistry held on September 27-28, 1977 in Schloss Auel.

A Workshop Conference on UDP-glucuronyltransferase was held in order to bring together different investigators specialising in a particular aspect of the enzyme. The intention was to find a basis for a closer cooperation between the different groups and to exchange ideas and methods making it possible to cross the hurdles facing those who work in the field of glucuronidation of endogenous and exogenous substances. The topics which were chosen for the meeting covered the following aspects: methods of determination of UDP-glucuronyltransferase activity; problems relating to the origin of the enzyme and the nature of the substrate; application of assays of UDP-glucuronyltransferase in clinical chemistry; enzyme-substrate interactions and factors influencing the enzymic reaction; the role of UDP-glucuronyltransferase in the entero-hepatic circulation of glucuronides, regulation and induction of UDP-glucuronyltransferase, with a subsection on solubilisation and purification.

Animals↗
PubMed1980

[Binding capacity of sex hormone binding globulin and corticosteroid binding globulin in serum of male patients with liver cirrhosis (author's transl)].

The binding capacities of SHBG and CBG were measured by agar gel electrophoresis in 63 men with cirrhosis of the liver and in 42 healthy male subjects. The normal range (X- +/- 2s) for SHBG was 8.3-17.1 microgram/l, for CBG 46.4-82.8 micrograms/l. SHBG binding capacity was significantly higher in men with liver cirrhosis (mean 18;1 microgram/l; p less than 0.001) but CBG binding capacity was significantly lower (mean 49.7 microgram/l; p less than 0.001). Although SHBG was lower in patients with decreased CBG binding capacity, a correlation between both steroid binding proteins did not exist. Moreover, there was no correlation between SHBG or CBG on one hand and other parameters of hepatic protein synthesis such as serum protein concentration, cholinesterase activity and the coagulation factors V and VII on the other hand. In contrast to liver cirrhosis, 12 patients with fatty liver and 11 patients with toxic fibrosis of the liver did not reveal changes in SHBG or CBG. Treatment with spironolactone (200 mg daily for one week in 9 subjects) did not change the steroid binding capacity of human serum.

Adult↗
PubMed1980

[Effects of rifampicin and streptomycin on the concentrations of testosterone and cortisol in the blood of men (author's transl)].

It has been shown previously that the biosynthesis and metabolism of oestrogens is affected by rifampicin. The present study was undertaken to investigate if rifampicin may also influence the plasma concentrations of testosterone and cortisol. Five male patients suffering from tuberculosis received rifampicin or streptomycin. During treatment with rifampicin testosterone concentrations were significantly elevated as compared to control conditions; this increase was found in the morning (8.00 h) as well as in the afternoon (16.30 h). When the same patients were treated with streptomycin, only irregular changes of testosterone concentrations were observed. The blood level of cortisol was increased in two patients, but unchanged in three patients who were treated with rifampicin. No changes at all were detected in patients under treatment with streptomycin. The results presented here show that rifampicin -- in contrast to streptomycin -- influences the biosynthesis of testosterone and possibly also that of cortisol.

Adult↗
PubMed1980

Biosynthesis of 16 alpha, 17 alpha-epoxy-oestratrienol in rat liver microsomes.

After incubation of 1,3,5(10),16-oestratetraenol, a 16-dehydrosteroid, with rat liver microsomes, 16 alpha, 17 alpha-epoxy-oestratrienol was isolated as metabolite. The compound was detected by the use of mass fragmentography after purification of the incubation extract by thin-layer chromatography. Since the epoxide is rapidly hydrolysed by a hepatic epoxide hydratase, only very small concentrations of this metabolite were present in the incubation extract. When styrene oxide was added to the incubation mixture as inhibitor of the epoxide hydratase, the yield of the steroid epoxide increased considerably. Final identification of the oestrogen epoxide was performed by recording mass spectra and by comparison with authentic reference material.

Animals↗
PubMed1980

Biosynthesis of 16 alpha, 17 alpha-epoxy-4-androsten-3-one in rat liver microsomes.

4,16-Androstadien-3-one was incubated with the microsomal fraction of male rat liver in the presence of a NADPH generating system and oxygen. The metabolites formed were extracted from the incubation medium and purified by thin-layer chromatography (tlc). Final identification was performed by combined gas liquid chromatography-mass spectrometry. Incubation of 4,16-androstadien-3-one resulted in the formation of a non-polar metabolite which proved to be 16 alpha, 17 alpha-epoxy-4-androsten-3-one. This epoxide is a shortlived intermediate which is rapidly hydrolysed by the microsomal epoxide hydratase to 16 beta, 17 alpha-dihydroxy-4-androsten-3-one. In order to increase the amounts of epoxide in the incubation mixtures, styrene oxide which is a potent inhibitor of the epoxide hydratase was added. Under these conditions, up to 8% of the 16-dehydro-steroid incubated was transferred to the 16 alpha, 17 alpha-epoxy-compound.

Androstane-3,17-diol↗
PubMed1979

Uptake of L-tri-iodothyronine by isolated rat liver cells. A process partially inhibited by metabolic inhibitors; attempts to distinguish between uptake and binding to intracellular proteins.

1. Rat liver cells obtained by dispersion with collagenase were used to investigate the mode of entry of L-tri-iodothyronine into the cell. 2. The hormone was taken up very rapidly at 23 degrees C; the linear phase of uptake lasted for up to approx. 20 s. 3. A plot of the initial rates of uptake against different concentrations of L-tri-iodothyronine yielded a sigmoidal curve. The Eadie--Hofstee plot (v/[S]2 versus v) yielded two straight lines. The uptake component with an apparent Kt value of 86 +/- 15 pM was designated as system I, and the second uptake component with an apparent Kt of 726 +/- 11 pM as system II. The Hill plot for system I was not linear; the apparent Hill coefficient for system II was calculated to be 2.1.4. Uptake of L-tri-iodothyronine by system I was higher at pH 6.4 than at pH 7.4; system II was relatively insensitive to changes in the pH of the external medium. 5. Both systems exhibited a transition temperature at about 16 degrees C in the Arrhenius plot. The activation energies of the two systems below and above 16 degrees C were 72.8 and 47.7 and 54.4 and 33.1 J/mol respectively. 6. Inhibitors of cellular energy reduced the uptake by system I to a larger extent than that by system II. 7. Replacement of Na+ in the external medium by either K+ or choline led to uptake that followed normal Michaelis--Menten kinetics. 8. Thiol-group-blocking agents reduced the uptake of the hormone by both systems. 9. Treatment of liver cells with beta-glucosidase, Pronase and neuraminidase led to a decrease in the uptake of L-tri-iodothyronine by system I, whereas uptake by system II was decreased after treatment with phospholipase A2, beta-galactosidase. Pronase and neuraminidase. 10. The stereoisomer D-tri-iodothyronine (100--3000 pM) did not affect system I, but uptake by system II decreased with increasing concentration of D-tri-iodothyronine. Reverse L-tri-iodothyronine (2--100 pM) and L-thyroxine (100--3000 pM) did not influence uptake by either system. 11. Under identical conditions of incubation, the uptake of L-tri-iodothyronine was 3.7 times higher than binding to cytosol proteins. The binding was insensitive to metabolic inhibitors. The results suggest that cytosol proteins are not directly involved in the uptake of L-tri-iodothyronine. 12. Plasma-membrane vesicles also take up the hormone rapidly at 23 degrees C. Increasing the osmolarity of the external medium led to a decrease in the uptake of L-tri-iodothyronine by vesicles. 13. Uptake as a function of L-tri-iodothyronine concentration exhibited a sigmoidal curve. The Eadie--Hofstee plot showed two uptake components with apparent Kt values of 96.8 and 1581 pM. 14. The results of our study are consistent with a carrier-mediated translocation of the hormone into the cell.

Animals↗